1. Technical Field
Embodiments of the invention generally relate to internal combustion engines. More particularly, embodiments relate to internal combustion engines that use water injection.
2. Discussion
The internal combustion engine (ICE), which is a cornerstone of the transportation and other industries, has long been the subject of considerable research. Many ICE's, such as standard four cycle and two cycle engines derive power from the combustion of fuel/air mixtures. For example, the ignition of hydrocarbon fuel, such as gasoline, propane, natural gas, or diesel is often used to force piston movement, which in turn rotates a crank shaft to transfer power to the wheels of a vehicle. Despite the popularity of these conventional ICE designs, a number of challenges remain. For example, in order to increase the power output of a conventional engine, it is often necessary to increase the number of combustion chambers (i.e., “cylinders”), which essentially provides the opportunity to increase the amount of fuel available for combustion over a given period of time. Unfortunately, this fuel increase tends to add to the cost of operation—particularly in situations where the price of fuel is relatively high.
Conventional ICE's also face significant obstacles with regard to toxic emissions. Indeed, the tightening of governmental emissions standards in the automotive industry is well documented and the subject of considerable debate. In order to meet these standards, automotive manufacturers may be under increased pressure to develop more advanced exhaust systems, such as enhanced catalytic converters, which can lead to increased manufacturing costs.
Another concern with conventional ICEs centers around the heat generated by the combustion cycle. In particular, engine designers are often forced to implement complex cooling systems to combat overheating. Other solutions involve constructing virtually all engine components out of high-temperature metals. Each of these solutions can further increase costs. In addition, any excess heat that is successfully removed from the system is generally treated as waste.
Although more recent engine development efforts have resulted in the design of a six cycle steam combustion engine, which uses two additional cycles to generate power from steam, there remains considerable room for improvement. In the six cycle engine, for example, once the combustion stroke has terminated and the exhaust gases have been lost and discharged via the exhaust stroke, water is injected in order to create vapor from the leftover heat. The vaporization pushes the piston down to develop a pressure steam stroke. At the end of the pressure steam stroke, a wet condition typically exists within the cylinder. As a result, the six cycle engine may fail to be as efficient as possible (or may be rendered inoperable) in cold weather environments.